Solution to the ambiguous "Configuration Error" - An error occurred loading a configuration file: Object reference not set to an instance of an object.
If you see this error message it means that you have not selected a .NET framework version to use for the website or virtual directory.
To resolve, go to IIS, properties of the site, ASP.NET tab and select the .NET framework version.
Description: **An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.
Parser Error Message: An error occurred loading a configuration file: Object reference notsetto an instance of an object.